1. Field of the Invention
The present invention relates to a constant velocity universal joint for connecting a first shaft as one transmission shaft and a second shaft as the other transmission shaft, for example, in a driving force-transmitting section of an automobile.
2. Description of the Related Art
Constant velocity universal joints are commonly used in motor vehicle applications. The constant velocity universal joint is disposed in a driving force-transmitting section of an automobile for connecting a first shaft as one transmission shaft and a second shaft as the other transmission shaft so that a rotary force is transmitted to respective axles.
The present applicant has proposed a constant velocity universal joint and an assembling method thereof in U.S. patent application Ser. Nos. 09/456,488 and 09/984,898, now U.S. Pat. Nos. 6,454,655 and 6,497,621, respectively. According to the constant velocity universal joint, induced thrust performance and durability are improved by reducing slide resistance generated when one transmission shaft is tilted and a trunnion is displaced along a guide track. The present invention has been made in relation to this proposal.
A general object of the present invention is to provide a constant velocity universal joint which makes it possible to easily assemble a trunnion and an annular member. The trunnion has a spherical surface along the circumferential direction thereof. The spherical surface is partially cut out into a variety of shapes. The annular member has a spherical recess having an inner circumferential surface corresponding to the spherical surface.
A principal object of the present invention is to provide a constant velocity universal joint which makes it possible to assemble a trunnion and an annular member regardless of orientation of assembling components.
Another object of the present invention is to provide a constant velocity universal joint having improved lubrication performance on a sliding plane between a spherical surface of a trunnion and a spherical recess of an annular member.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.